Is this a bug ?

Sorry, no.
My intention was to play knight e7 to c6 and not Kc8-Kb7 with move 27.

I was forced to play Kc8-Kb7 because knight e7 to c6 was not possible, i should have been able to make this move, my king is not pinned in any way.

Move 26 was a move that Widemaxx made, not me.

You played 26...Kb7 i.e. move 26 not 27 as you state.
You could have played 26...Nc6 if you wanted, though that would lose a piece to 27 Rc7+.
Then your opponent played 27 Bf6, attacking your Ne7. So it makes sense you wanted to move it then, but you were not allowed because it was pinned.
I guess you recollect the events of this blitz game somehow incorrectly. This at least makes everything understandable in a rational way without recourse to bugs, witchcraft, or conspiracy.

I see your point, i made a mistake with move 27, it was move 26 indeed.

However, i will state this one more time: i was not able to play Nc6 at move 26 as i intended ! therefore i played kb7.

Thats the whole point in this tread from the beginning.